(a) Field of the Invention
The present invention relates to a golf club head, especially so-called an iron golf club head or a putter golf club head.
(b) Description of Prior Art
It is mainly for the purpose of enlarging so-called a sweet area and lowering the center of gravity of a golf club head that the weight distribution of a golf club head including an iron golf club head or the like is adjusted in an invention related to a golf club head. It is well recognized by those skilled in the art that to enlarge a sweet area, the center of gravity of a club head should be positioned comparatively backward, and/or, the weight distribution of a golf club head should be concentrated upon a peripheral portion of a main body of a head besides the enlargement of a bulk of a golf club head itself. On the other hand, it is mainly for the purpose of making a golf ball travel more upwardly and a longer distance to lower the center of gravity of a club head. One of the representative of a means for realizing such weight distribution is disclosed in U.S. Pat. No. 3,847,399, in which a head body is formed hollow, or a back surface of a club head is formed with a cavity.
However, especially for an iron club head, it is difficult to make the same hollow. Further, only a cavity formed in a back surface of a club head made of a single material cannot sufficiently concentrate the weight distribution of a club head upon a peripheral portion, thus setting limits to enlargement of a sweet area. Furthermore, although there is proposed another golf club head where a balance weight made of beryllium copper alloy is secured to a lower side of the back of the head body made of the titanium alloy without weighting the whole weight any more, which structure yet has set limits to enlargement of a sweet area as well.
As described above, as conventional iron or putter golf club heads have been formed integral as a whole, a relatively smaller sweet area have been attained, which has been also resulted with respect to the above prior golf club head having the denser balance weight secured to the lower side of the back.